I have a confession to make: I live in fear of the semicolon. As phobias go, I know it could be worse. I could have an aversion to, say, spiders, or maybe conference calls or my BlackBerry. Which would really be unfortunate, since I work in marketing. Anyway. I’m tired of worrying about run-on sentences. And choppy prose. And whether or not the proofreading team is making fun of me behind my back. Can you help me?

My dear Subject,

I pray that I will not perturb you further when I admit that the semicolon is my favorite punctuation mark. Yes, even the Grammar Queen plays favorites—but how can I not, when considering such an elegant and subtle tool? But fear no more; you’ve already made the first and most important step, admitting that you have a problem. And soon you too could be reclining among the topiary in your east garden; sipping a nice Chateau Lafite; and admiring the semicolon mastery of such luminaries as Henry James, E.M. Forster, and (may I confess an unexpected pleasure?) David Foster Wallace.

But let us first lay out the rules. Semicolons have three main functions:

A semicolon separates items in a list when one or more of those items contains one or more commas. In this case, the semicolon functions as a kind of supercomma, allowing the reader to parse a nested list without confusion. Felicity was known for her stellar taste in wedding presents. Her gifts to William and Kate included a hunting lodge; a 1963 Aston Martin convertible; and a selection of cheeses produced on her award-winning dairy estates at Wexford, Inverness, and Wokingham.

A semicolon combines two related independent clauses into a single sentence without need for a conjunction (and, but, etc.). Here the semicolon takes on its other role, that of a more refined and subtle cousin to the period. She packed each wedge of cheese herself; her favorite wrapping was a subtle floral chintz.

In a related usage, a semicolon is used before a conjunctive adverb connecting two related independent clauses. Kate loved the car; however, she was less fond of the Lymeswold, especially after Wills left it in the glove box for a week. (Other common conjunctive adverbs: therefore, moreover, in addition. Note also the comma following however.)

Take these rules to heart, and you’ll be well equipped to try out your new skill. If nerves linger, you might practice first on supportive friends and household staff before bravely employing the occasional semicolon in business correspondence. I have the utmost faith that it will enrich both your writing and your career.